Abstract

Introduction

Collagen peptides have been reported to possess various biological activities for
various cell types. The purposes of this study were, first, to examine the therapeutic
effects of collagen tripeptide (Ctp) in rabbit osteoarthritis and, second, to explore
a synergetic effect with hyaluronan (HA).

Methods

Osteoarthritis was induced by anterior cruciate ligament transection of the right
knee in 72 Japanese white rabbits and they were divided into four groups (control,
Ctp, HA and Ctp/HA). Each material was injected weekly into the knee, and knee joint
samples were collected 5, 10 and 15 weeks after surgery. Macroscopic and histomorphological
analyses of cartilage were conducted. Expression of type II collagen and matrix metalloproteinase-13
was also analyzed immunohistochemically. A Tukey's honestly significant difference
test was used to evaluate the statistical significance of difference in the macroscopic,
histological and immnohistochemical results.

Results

All treatment groups exhibited slightly higher resistance to the progression of osteoarthritis
than the control group macroscopically 15 weeks after surgery. Histologically, intra-articular
injection of Ctp significantly reduced cartilage degradation 10 weeks after surgery,
and Ctp/HA significantly reduced it 5 weeks after surgery in comparison with the control.
Immunohistochemically, both Ctp-treated and Ctp/HA-treated groups had significantly
increased type II collagen-positive chondrocytes at the fifth week after the surgery,
although the numbers of matrix metalloproteinase-13-positive chondrocytes were not
affected.

Conclusion

Periodical injections of Ctp and Ctp/HA delayed progression of cartilage degeneration
of early osteoarthritis induced by anterior cruciate ligament transection in rabbits.
This effect appears to be exerted by promotion of type II collagen synthesis predominantly.